A passive optical network (PON) is one system for providing network access over “the last mile.” The PON is a point to multi-point network comprised of an optical line terminal (OLT) at the central office, an optical distribution network (ODN), and a plurality of optical network units (ONUs) at the customer premises. In current PON systems, the OLT broadcasts a downstream optical signal to the plurality of ONUs via the ODN. The downstream optical signal may be a wavelength division multiplexed (WDM) optical signal comprising a plurality of wavebands (e.g., optical channels carrying an individual optical signal), where each waveband is assigned to a corresponding ONU or cluster of ONUs. Upon reception, each ONU may filter out wavebands assigned to other ONUs from the WDM downstream optical signal to isolate their assigned waveband. This may allow the ONU to obtain its own optical signal (i.e., the optical signal intended for the ONU), while ignoring optical signals intended for other ONUs. Some PONs may have one or more control and/or management channels, such as the physical layer operations, administration, and maintenance (PLOAM) channel described in International Telecommunications Union (ITU) Standardization Section (ITU-T) publication G.984.3, which is incorporated by reference herein as if reproduced in its entirety.
One of the central goals in communications technology is to reduce power consumption without substantially reducing service quality. Currently, information and communications technology account for between two percent and ten percent of worldwide energy consumption. Consequently the governments of many countries have begun to promulgate and enforce energy efficiency regulations aimed at communications providers. PONs are generally more energy efficient than conventional copper wire access technologies, e.g., Digital Subscriber Line (DSL) and coaxial cable (coax), but optical access nevertheless consumes a substantial amount of global energy resources. Specifically, approximately eighty million fiber to the premises (FTTP) users consume between five and ten terawatt (TW) hours (TWhrs) of electricity per year.
ONUs have been identified as an area of focus for reducing energy consumption in PONs because they consume more than 60 percent of the total power in the PON. Additionally, ONUs may potentially achieve significant power savings without substantially reducing service quality because ONUs oftentimes experience extended idle periods (e.g., periods where little or no downstream information is being sent or received), and therefore a reduction in performance during these periods (e.g., due to power savings measures) may not substantially reduce effective service quality as perceived by the client.